another idle problem

[cat-vi]

Hi,
I got a idle problem, engine is hunting until it dies, too keep it running I have to pump the gas pedal just like a old caburated engine.
As soon as I have slightly load at the engine by running up a hill, it is running very smothly all the way down to abt. 1000 rpm. I have searched in the forums for idle problem but can not quite find anny thread covering my problem, what is the first thing I should check up, should I try to replace the "Idle Control Motor" or is there annything else I should check up first?

Another issue I have is, at wide open throttle the throttle position read 91,5%, when I look at the throttle blade they are 100% open, should I purchase a new throttle position sensor as well or is there a way to adjust this on the software for the ecm (bigstuff3)

Any advice would be highly appreciated.

 

[BMFB]

Re: another idle problem

dude its gotta be the MAF

i would look into the IAC first myself, (thing you said). they get clogged up, or just break sometimes. You should be able to remove it, plug it in and turn your key on, and watch it back out while you hold it in your hand(need a friend) if its moving thats a good start. clean the ports up while your in there with some carb cleaner.

I point to this because you say it runs fine otherwise, but will not idle. few things will do that.

 

[cat-vi]

Re: another idle problem

dude its gotta be the MAF

i would look into the IAC first myself, (thing you said). they get clogged up, or just break sometimes. You should be able to remove it, plug it in and turn your key on, and watch it back out while you hold it in your hand(need a friend) if its moving thats a good start. clean the ports up while your in there with some carb cleaner.

I point to this because you say it runs fine otherwise, but will not idle. few things will do that.

Man, you're fast, I barly manage to post before you got a good advice, thanks allot, I will take it out and check, you'll be informed about what I find.

 

[BMFB]

Re: another idle problem

The maf part was a joke, but for the idle that would be a goo dplace to start after that, its vacuum lines, but it would usually show other symptoms if it was that bad to mess up the idle

 

[Espritmike]

Re: another idle problem

Mine had an idle issue (still idles a little erratic) and would stall when any load was put on the motor. It ended up being a bad distributor. The magnets were weak.

 

[BMFB]

Re: another idle problem

thats a weird one, I've never heard of that. I've had the pickup go bad on a distributor, but not the magnets.

 

[cat-vi]

Re: another idle problem

The maf part was a joke, but for the idle that would be a goo dplace to start after that, its vacuum lines, but it would usually show other symptoms if it was that bad to mess up the idle

I took out the IAC, when I turned on the ignition valve-rod was not moving, when I switch the ignition off the rod moved outward, ignition on no movement, ign. off and rod moved further out until all threads was out and the spring made sure the rod went all across the garage into some boxes with parts:rant: Should I see movement both ways with the IAC out or will the spring do the job when it is installed? I cleaned up the passages for the IAC, but no change. I took off the distributor cap, all looks pretty good though, this is a quite new MSD unit with a external blaster coil.
MAF:lol: I think I figured, I installed a 3 bar MAP so I do belive adding a MAF would be a bit more info for the ECU than it would appreciated:lol: thanks tough:tup:

Any other ideas:roll:

 

[UR50SLO]

Re: another idle problem

Did you say your running BigStuff3 On it?

There is all kinds of perameters to work on the IAC control.

I'd make sure on your timing map that the numbers at idle are close.. Meaning if your target idle
cells are 20deg that most of the other cells in that area are 20. So timing isn't jumping all around.

Second.. where is your actual Air Fuel Ratio at idle? (Should be on your BS3) Need that number
Get it to be in the 13AFR range.

Then... you can play with the IAC perameters... Timing and fuel first.. then IAC last.

The IAC has settings on how quickly it reacts to RPM changes....load/ect.

Good luck!
~Scott

 

[BMFB]

Re: another idle problem

oh yea I didn;t even see you were running bs3 stuff, do you have any logging capibilitys? or at least being to connect and see what your trucks doing from the ALDL connector?

 

[cat-vi]

Re: another idle problem

Did you say your running BigStuff3 On it?

There is all kinds of perameters to work on the IAC control.

I'd make sure on your timing map that the numbers at idle are close.. Meaning if your target idle
cells are 20deg that most of the other cells in that area are 20. So timing isn't jumping all around.

Second.. where is your actual Air Fuel Ratio at idle? (Should be on your BS3) Need that number
Get it to be in the 13AFR range.

Then... you can play with the IAC perameters... Timing and fuel first.. then IAC last.

The IAC has settings on how quickly it reacts to RPM changes....load/ect.

Good luck!
~Scott

Yes, it got the bigstuff3 with syty harness delivered by Campbell, (great guys by the way) I have barely been able to try it out yet, but the BS3 was delivered with a base tune for syty, I am aware that this need some tuning, and this is most likely above my knowledge, so I need to find a tuner who can look into it, but I will try your advice by setting the ignition point around idle at abt. 20 or so to see if it gets more stabile. When I look at the AFR it seems like it is around 13 but this is also hunting, reading 17 when engine is about to die. I will have to try to figure out how save a log. It is almost at freeze point here and I have removed the windshield so it is a bit frisky to say at least.
Thanks for the advice and for wishing me good luck (I realy need that:lol

 

[cat-vi]

Re: another idle problem

oh yea I didn;t even see you were running bs3 stuff, do you have any logging capibilitys? or at least being to connect and see what your trucks doing from the ALDL connector?

Yes, it is possible to do logging, I just have to figure out how, I can see at the laptop what is going on, that is not the problem, the problem is what to do about it and I was hoping to have it idle a bit better before doing some try-out, it is very "troublesome" to lump around with a car that need some load to be able to run at all. To be continued....:tup:

 

[cat-vi]

Re: another idle problem

oh yea I didn;t even see you were running bs3 stuff, do you have any logging capibilitys? or at least being to connect and see what your trucks doing from the ALDL connector?

I saved a log, engine was a bit cold, so idle rpm was on the higher side, I set the ignition at 20 dgr. in the idle area, engine is starting with AFR at 13.1 and running good for a few sec. then start running lean at 15.9 and rpm dropping down to 500 rpm, then rpm picks up to 1600 and AFR reading could be as rich as 9.5 - 10.0 for a very short period of time before it start running lean and rpm drop. I have no idea how to place the log here, I tried to send it as an attachment on mail, that is working OK, but it will show up as raw data only, I guess it needs to be opened with the bigstuff software. When I restart the engine when warm I need to activate the accelrator quite a lot to have it fire, I guess this indicates to much fuel. Any ideas guys? I am not trying to have all your knowledge for free, I would just love to have the truck driveable enough to lump around to get som better logging. I'll contact Campbell Automotive to ask if they offer tuning service over mail by sending log as attachment, if possible, anybody done something like that?

 

[BMFB]

Re: another idle problem

wow...alright

so that I get this straight, you have installed the BS3 with a base tune. Now, since you have installed this, has the truck run and idled correctly, or did it start with this issue the moment that the bs33 was installed?

 

[cat-vi]

Re: another idle problem

wow...alright

so that I get this straight, you have installed the BS3 with a base tune. Now, since you have installed this, has the truck run and idled correctly, or did it start with this issue the moment that the bs33 was installed?

I manage to install the bs3 only days before I had to go back at sea in December, at this time it was winter big time, and I did not have a chanse to try it ou,t but was running the engine at idle in the garage until I felt dizzy, first time I started the engine it was idling good when cold, but when becoming warm it start to hunt, but now it seems like this is the issue all the way from cold engine.
The hunting issue was allmost as bad with the original ECU, but it seems like it is getting wors, so thats why I thought it might be a mechanical issue in the first place, but now I think I got two loose ends, both mechanical and tune issue. If I start any tuning with a mechanical problem not solved I guess I will just be digging myself deeper until I'm up to my neck in problems.